In wireless voice and data communications, it is desirable to maximize the number of users in a base transceiver station (BTS) sector while at the same time providing high signal quality (i.e., high SNR) for the users. One way to achieve both conditions is through the use of a beam forming antenna. A BTS can generate plural directed beams by employing an antenna array and digitizing signals transmitted to and received from the antenna array in a weighted manner (i.e., amplitude and/or phase) that produces the plural beams. Since the beams have high gain in the direction of the main lobe of the composite beam, high SNR is achieved. And, since the BTS can change the weights associated with each antenna element in the array to cause the beam to scan, a high gain can be maintained throughout the duration of a user's wireless connection with the base station.
FIG. 1 is a schematic diagram of a wireless communications network 100 having three base transceiver stations 105a, 105b, 105c. 
The first BTS 105a provides three beams 107a, 107b, and 107c produced by beam forming. The first beam 107a is used for communicating to a first user 109a in the first BTS sector. The first user 109a is inside a building 108. Because the first beam 107a is produced through the use of beam forming, it has excess link margin to allow deeper penetration into the building 108 for communicating with the user 109a. Further, multi-path noise caused by a beam reflecting off other buildings is minimized or avoided due to the formed beam 107a. 
The first BTS 105a produces a second beam 107b to communicate with a second user 109b in the first BTS sector. In this case, the second beam 107b is purposely kept short so as to reduce pilot pollution where BTS sectors intersect.
The first BTS 105a also produces a third beam 107c for communicating with a third user 109c in the first BTS sector. Similar to the first beam 107a, the third beam 107c reduces multipath noise effects due to its directiveness. Also, the third user 109c is closer to the third BTS 105c; but, because of the high gain produced by beam forming, the third beam 107c of the first BTS 105a is able to reach the third user 109c to assist the third BTS 105c, which is heavily loaded with other users, as will be discussed.
The antenna gain is proportional to 20LOG(number of elements) plus vertical gain. For example, for a sixteen element array four feet wide, the beam forming may provide over thirty-seven dB versus fifteen dB for conventional antennas.
The second BTS 105b provides two beams, 111a, 111b produced by beam forming. The first beam 111a communicates with a first user 113a in the second BTS sector. The second beam 111b provides a link to a second user 113b in the second BTS sector. Because of the high-link margin produced by beam forming, sparse initial deployment provides lower initial capital requirements for the wireless communications network 100.
The third BTS 105c is able to provide four beams 115a, 115b, 115c, 115d in a beam forming manner to communicate with high-gain to four users 11 7a, 117b, 117c, and 117d, respectively.
As can be seen from the beams 107, 111, 115 produced by the base transceiver stations 105, the use of beam forming eliminates noise problems caused by multipath, pilot signal pollution, and interference from signals from adjacent base transceiver stations. Further, the high gains afforded by the beams produced by the beam forming provides a so-called virtual point-to-point RF effect.
FIG. 2A is a block diagram of the prior art base transceiver station 105a. The base transceiver station 105a has an antenna assembly 205, base electronics 210, and base station tower 215. The base electronics 210 comprise transceivers 220, weighting electronics (e.g., Butler Matrix, FFT or other) 225, and user channel cards 230.
As shown in detail in FIG. 2B, the transceivers 220 each comprise a transmitter 235, receiver 240, and duplexer 245. The duplexer 245 is coupled to a single element 255 in a sector antenna array 250, as shown in FIG. 2C. The coupling between the transceivers 220 and the elements 255 of the sector antenna array 250 is made via parallel cables 265a, 265b, 265c, and so on The number of parallel cables used is equal to the number of transceiver/element pairs. Each cable is expensive, heavy, and sensitive to temperature changes. Similarly, the transceivers are expensive, relatively large in size, and sensitive to temperature and humidity changes.
Continuing to refer to FIG. 2A, extending upward from the base electronics 210 is an antenna assembly support pole 260, on which the sector antenna array(s) 250 is/are supported. Typically, antenna assembly support pole 260 is capable of supporting nine parallel cables 265. Because (i) it is useful to have three sector antenna arrays 250 for transmitting and receiving in 360° and (ii) each sector antenna array 250 preferably includes at least four elements 255, nine parallel cables 265 is limiting to the capacity of the base transceiver station 105a. 